tracing: Remove unused ftrace_cpu_disabled per cpu variable

Since the ring buffer is lockless, there is no need to disable ftrace on
CPU. And no one doing so: after commit 68179686ac67cb ("tracing: Remove
ftrace_disable/enable_cpu()") ftrace_cpu_disabled stays the same after
initialization, nothing changes it.
ftrace_cpu_disabled shouldn't be used by any external module since it
disables only function and graph_function tracers but not any other
tracer.

Link: http://lkml.kernel.org/r/1446836846-22239-1-git-send-email-0x7f454c46@gmail.com

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 0 insertions, 6 deletions

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 92382af7a213..a663cbb84107 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -288,9 +288,6 @@ int __trace_graph_entry(struct trace_array *tr,
         struct ring_buffer *buffer = tr->trace_buffer.buffer;
         struct ftrace_graph_ent_entry *entry;
 
-        if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
-                return 0;
-
         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
                                           sizeof(*entry), flags, pc);
         if (!event)
@@ -403,9 +400,6 @@ void __trace_graph_return(struct trace_array *tr,
         struct ring_buffer *buffer = tr->trace_buffer.buffer;
         struct ftrace_graph_ret_entry *entry;
 
-        if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
-                return;
-
         event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
                                           sizeof(*entry), flags, pc);
         if (!event)